North Carolina Tar Heels basketball's bid into the NCAA Tournament sent social media through a whirlwind on Sunday night as many believed they shouldn't have entered the bracket.

No. 6 BYU is the classic risky pick to make a deep run that could win you your bracket pool or lose it for you on Day 1.

It's the first time in school history that the Bruins are the top team in the tournament. They had two losses on the season, both of which came to the Trojans.

From the run on SEC squads to power-conference teams looking for a breakthrough to the players you need to know, here is a primer on March Madness.